Medical valve with positive flow characteristics

ABSTRACT

A valve for selectively permitting a fluid flow between first and second medical implements is disclosed. The valve has a housing with an interface suitable for receiving a connector portion of a first medical device such as a catheter, and a seal made of a flexible material. The seal has a first end in fluid communication with the interface, a second end suitable for receiving the second medical device, and at least one slit in fluid communication with the first end and the second end. The slit defines a restricted fluid flow path and a relatively small interior volume when in an undisturbed state, defines an expanded fluid flow path and a larger interior volume upon the introduction of the second medical instrument into the slit, and retracts to define a restricted flow path and a small interior volume upon the withdrawal of the second medical device from the seal.

RELATED APPLICATION

[0001] This application is a continuation of U.S. patent applicationSer. No. 09/614,001, filed Jul. 11, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates generally to a medical valve, and inparticular to a valve which, when connected between a first medicaldevice, such as a fluid source, and a second medical device, such as acatheter, facilitates fluid flow therebetween, and when the firstmedical device is disconnected therefrom, induces a positive flow offluid through the valve in the direction of the second medical device.

[0004] 2. Description of the Related Art

[0005] The manipulation of fluids for parenteral administration inhospitals and medical settings routinely involves the use of connectorsand valves for selectively facilitating the movement of fluids betweentwo points. These valves are typically placed along a fluid flow lineleading to a patient or other destination. For example, the tube maylead to a catheter having its tip positioned within a patient.

[0006] The valve is arranged so that a fluid source or other line may beconnected thereto for providing a fluid flow from the source to thepatient. When the fluid source or line is removed, the valve closes,sealing the line leading to the patient.

[0007] The element which is connected to the valve may comprise a tubeor other medical device such as a conduit, syringe, IV set (bothperipheral and central lines), piggyback line, or similar componentwhich is adapted for connection to the medical valve. Unfortunately,prior art valves suffer from a problem arising from the disconnection ofthese medical devices from the valve.

[0008] These valves define a space within them through which a fluid orother material may flow from the device to the line on which the valveis mounted. When the medical device is connected to the valve, ittypically occupies a portion of this internal valve space, displacingthe fluid (whether it be a liquid or air) within the valve.

[0009] A problem arises when the medical device is disconnected from thevalve. When the device is disconnected, it no longer occupies a portionof the space in the valve. The increase in space within the valve causesthe fluid in the valve and line to which the valve is connected, to moveto fill the space. In effect, the removal of the device creates asuction force which draws fluid into the valve.

[0010] In the medical setting, this movement of fluid is veryundesirable. When the valve is connected to a fluid line leading to apatient, the movement of fluid through the line towards the space in thevalve has the effect of drawing blood from the patient in the directionof the valve. A serious problem may result in that this blood may clotand clog the catheter near its tip, rendering it inoperable, and mayeven result in a clot of blood in the patient, which may prove fatal.

[0011] One attempt at overcoming this clogging problem has been to coatthe inner surface of the catheter near its tip in order to prevent bloodfrom sticking to its interior surfaces. This method has generally beenunsuccessful in preventing clogging of the catheter.

[0012] The risk of blood clogging of the catheter is significantlyheightened where the inner diameter of the catheter is small (e.g., 27gauge). These small catheters have the advantage, however, in that theyreduce the trauma and discomfort caused by insertion into a patient.Because these catheters have a very small passage therethrough, even asmall suction force may draw sufficient amount of fluid back through acatheter toward the valve to introduce blood into the catheter tip,which blood may clog the catheter's passage.

[0013] Overcoming the above-stated problem is made more difficult whenconsidering other criteria which the valve must satisfy. For example,the valve should be arranged to so that it does not have any fluidstagnation points. If the fluid is allowed to stagnate in one or moreareas of the valve, bacteria growth and other problems may occur.

[0014] In addition, the valve should have an internal flow path which issmooth. Sharp edges and corners may damage blood cells and causehemolysis.

[0015] A valve that overcomes the above-stated problems is desired.

SUMMARY OF THE INVENTION

[0016] In accordance with one preferred embodiment, a medical valve forselectively permitting fluid to flow between a first medical device anda second medical device comprises a housing that has an interfacesuitable for receiving a connector portion of the first medical device,and a seal. The seal is made of a flexible material and has a downstreamend in fluid communication with the interface, an upstream end suitablefor receiving the second medical device, and a normally substantiallyclosed passage in fluid communication with the downstream end and theupstream end. The passage has a relatively small interior volume when inan undisturbed state and a larger interior volume upon the introductionof the second medical instrument into the upstream end of the passage.The passage retracts to define a restricted flow path and a relativelysmall interior volume upon the withdrawal of the second medical devicefrom the seal (the upstream end initially being sealed as the secondmedical device is withdrawn) so that a fluid occupying the interiorvolume is forced toward the downstream end as the passage wallscollapse.

[0017] In accordance with another preferred embodiment there is provideda valve seal for use in a medical valve having an interface for fluidcommunication with a first medical device. The seal comprises a firstend in fluid communication with the interface, a second end suitable forreceiving a second medical device, and at least one slit in fluidcommunication with the first end and the second end. The slit defines arestricted fluid flow path and a relatively small interior volume whenin an undisturbed state, and defines an expanded fluid flow path and alarger interior volume upon the introduction of the second medicaldevice into the slit. The slit retracts to define a restricted flow pathand a relatively small interior volume upon the withdrawal of the secondmedical device from the seal.

[0018] In accordance with another preferred embodiment a method isprovided for causing a positive flow in the direction of a first medicaldevice from a valve that connects the first medical device to a secondmedical device and has an associated seal. The seal is adapted toreceive at least a portion of the second medical device and providefluid communication between the first and second medical devices. Themethod comprises the steps of withdrawing the second medical device fromthe seal and

[0019] permitting the seal to retract from a large interior volume to arelatively small interior volume so as to displace any fluid within theseal in the direction of the first medical device.

[0020] In accordance with another preferred embodiment there is provideda method of preventing blood from flowing out of a patient into acatheter when a syringe is withdrawn from a valve between the syringeand the catheter. The method comprises the steps of connecting thedownstream end of the valve to the catheter and inserting the end of thesyringe into a slit forming the upstream end of a normally substantiallyclosed seal passage that is located in a resilient seal and is in fluidcommunication with the downstream end of the valve. This causes the sealpassage to open while providing sealing contact between the syringe andthe upstream end of the seal passage. The method further comprises thesteps of injecting fluid from the syringe through the seal passage tothe catheter and into the patient, and withdrawing the syringe, allowingthe walls of the seal passage to return to their substantially closedposition while initially maintaining sealing contact between theupstream end and the syringe. This provides a force urging fluid in thepassage toward the catheter.

[0021] In accordance with another preferred embodiment there is provideda medical valve for selectively permitting fluid to flow between a firstmedical device and a second medical device through an associated seal.The valve comprises an interface suitable for receiving a connectorportion of the first medical device, and a seal holder in fluidcommunication with the interface.

[0022] In accordance with another preferred embodiment a system foradministering fluid to a blood vessel of a patient comprises a catheterhaving an upstream end and a downstream end that is suitable forplacement in fluid communication with the blood vessel, and a syringesuitable for expelling fluid into the catheter. The system furthercomprises a valve having a fitting suitable for connection to theupstream end of the catheter and providing selective fluid communicationbetween the syringe and the catheter. The valve further comprises a sealmade of a flexible material. The seal has a downstream end in fluidcommunication with the fitting, an upstream end suitable for receivingthe syringe, and a normally substantially closed passage in fluidcommunication with the downstream end and the upstream end. The passagehas a relatively small interior volume when in an undisturbed state anda larger interior volume upon the introduction of the syringe into theupstream end of the passage. The passage retracts to define a restrictedflow path and a relatively small interior volume upon the withdrawal ofthe second medical device from the seal (the upstream end initiallybeing sealed as the syringe is withdrawn), so that a fluid occupying theinterior volume is forced toward the downstream end as the passage wallscollapse.

[0023] In accordance with another preferred embodiment there is provideda method of making a medical valve seal of the type having a body madeof a flexible material and at least one slit formed within the bodybetween adjacent first and second slit walls. The method comprisesmolding first and second preforms, each preform comprising one of thefirst and second slit walls and a perimeter edge portion, and pressingthe first and second preforms together so that the first and second slitwalls face each other. The method further comprises molding anadditional amount of a flexible material to at least part of theperimeter edge portions of the first and second preforms so that thefirst and second preforms and the additional material form a unitarymass with the slit formed therein.

[0024] For purposes of summarizing the invention and the advantagesachieved over the prior art, certain objects and advantages of theinvention have been described herein above. Of course, it is to beunderstood that not necessarily all such objects or advantages may beachieved in accordance with any particular embodiment of the invention.Thus, for example, those skilled in the art will recognize that theinvention may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

[0025] All of these embodiments are intended to be within the scope ofthe invention herein disclosed. These and other embodiments of thepresent invention will become readily apparent to those skilled in theart from the following detailed description of the preferred embodimentshaving reference to the attached figures, the invention not beinglimited to any particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Having thus summarized the general nature of the invention andits essential features and advantages, certain preferred embodiments andmodifications thereof will become apparent to those skilled in the artfrom the detailed description herein having reference to the figuresthat follow, of which:

[0027]FIG. 1 is a schematic view of the use of a valve in accordancewith the invention to interconnect a catheter with a fluid source such asyringe;

[0028]FIG. 2 is a perspective view of the valve;

[0029]FIG. 3 is a front elevation view of the valve;

[0030]FIG. 4 is a side elevation view of the valve;

[0031]FIG. 5 is a perspective view of a seal for use in the valve;

[0032]FIG. 6A is a front elevation view of the seal;

[0033]FIG. 6B is a front cross-sectional view of the seal;

[0034]FIG. 7A is a side elevation view of the seal;

[0035]FIG. 7B is a side cross-sectional view of the seal;

[0036]FIG. 8A is a front elevation view of the seal;

[0037] FIGS. 8B-8D are cross-sectional schematic views of the insertionof a medical device into the seal taken through lines 8B-8B, 8C-8C and8D-8D of FIG. 8A, respectively;

[0038]FIG. 9 is a front cross-sectional view of a housing for use in thevalve;

[0039]FIG. 10 is a side cross-sectional view of the valve and thesyringe before insertion of the syringe into the valve;

[0040]FIG. 11 is a side cross-sectional view of the valve with thesyringe fully inserted;

[0041]FIG. 12 is a front cross-sectional view of the valve with thesyringe fully inserted;

[0042]FIG. 13 is a side cross-sectional view of the valve with thesyringe partly withdrawn;

[0043]FIG. 14 a side cross-sectional view of the valve with the syringefurther withdrawn in comparison to FIG. 13;

[0044]FIG. 15 is a side elevation view of an alternative embodiment ofthe valve, with the syringe partly inserted;

[0045]FIG. 16 is a side elevation view of an alternative embodiment ofthe valve, with the syringe fully inserted;

[0046]FIG. 17 is a front elevation view of the valve as used with asyringe having a Luer lock;

[0047]FIG. 18 is a side elevation view of an alternative embodiment ofthe valve housing;

[0048] FIGS. 19A-19E are schematic views of a process of making theseal; and

[0049]FIG. 20 is a plan view of an overmold plate used in making theseal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0050] FIGS. 1-9 depict a valve 20 in accordance with a preferredembodiment of the invention. FIG. 1 illustrates a particular use of thevalve 20 to which it is well suited. Of course, the valve 20 may be usedin a variety of other manners.

[0051] As illustrated in FIG. 1, the valve 20 may advantageously be usedto selectively control the flow of fluid to a first medical device (suchas a catheter 22 shown here) from a second medical device (generallycomprising a fluid source such as an ISO standard syringe 24). In thisarrangement, the catheter 22 is connected to one end of the valve 20 andhas a tip 26 inserted into the arm of a patient. The syringe 24 has acannula tip or Luer 28 that is inserted into the other end of the valve20, which is designed to accept the Luer 28 of the syringe 24 without aneedle installed on the Luer.

[0052] When so connected, the valve 20 permits fluid to flow from thesyringe 24 to the catheter 22 and into the patient. The valve 20 is alsoarranged so that when the syringe 24 is disconnected, fluid flow throughthe valve 20 is prevented. In addition, when the syringe 24 isdisconnected, the valve 20 generates a “positive” fluid flow, i.e. flowof fluid in the direction of the patient, thereby preventing blood fromentering the catheter 22 and causing the associated adverse effects.

[0053] FIGS. 2-4 depict one preferred embodiment of a valve 20 inaccordance with the invention. The valve 20 comprises a relatively rigidhousing 30 and a relatively flexible and resilient seal 32 disposed onor within the housing 30. The housing 30 has a Luer lock interface 34 atits lower end to facilitate connecting the valve 20 to a variety ofmedical devices. One skilled in the art will readily appreciate that anumber of other interface or connection types are suitable for use inplace of the Luer lock 34, such as a Luer slip connection or a barbedhose fitting.

[0054] The seal 32 has a slit opening 36 (best seen in FIG. 2) which isconfigured to permit the Luer 28 of a syringe 24 (see FIG. 1) to enterthe seal 32 upon application of moderate pressure by the user. Thesyringe Luer 28 thus enters a slit 38 (see FIG. 3) formed in theinterior of the seal 32. With the syringe Luer 28 thus inserted, theseal permits fluid ejected from the syringe 24 through the Luer 28 toflow through the slit 38 and Luer lock 34 and into the catheter 22 orother medical device attached to the Luer lock 34.

[0055] FIGS. 5-7B show the seal 32 removed from the housing for purposesof clarity. The seal 32 has a body 40 which may take the form of a slabhaving a flat, generally rectangular shape. Like the entirety of theseal 32, the body 40 is preferably formed of molded, 50 durometersilicone rubber, or is alternatively formed of synthetic polyisoprene.At one end of the body 40 is formed a flat, generally rectangular neck42 and a generally circular transverse flange 44. The neck 42 issituated between first and second lateral extensions 43 a, 43 b whichhave shoulders 43 c, 43 d comprising those portions of the lateralextensions nearest the flange 44. The body 40, neck 42 and flange 44thus form an integral unit, inside of which is formed the (preferablysubstantially planar) slit 38. The slit 38 extends from the slit opening36 (best seen in FIG. 2) in the flange 44 to a lead lumen 46 formed inan end of the body 40 opposite the flange 44. The lead lumen 46 ispreferably substantially cylindrical and centered about an axis that issubstantially parallel to or collinear with the longitudinal axis of theseal. The slit 38 is preferably substantially planar and of virtually nothickness unless a Luer is connected. The slit 38 thus forms (in itsundisturbed state, i.e. when the syringe Luer 28 has not been insertedinto the seal 32) a highly restricted fluid flow path from the slitopening 36 to the lead lumen 46. As used herein in reference to a flowpath, “restricted” means a flow path that permits either no fluid, or aclinically negligible amount of fluid, to pass.

[0056] The preferred configuration of the slit 38 and lead lumen 46 isbest seen in FIGS. 6A-7B. The slit 38 has a body portion 48 within thebody 40 of the seal 32. Advantageously, the body portion 48 is a regionof maximum width, preferably about 0.228″, of the slit 38. The slit 38tapers to a point or region 50 of minimum width, which is preferablylocated within the neck 42. Advantageously, at the region 50 of minimumwidth the slit 38 is preferably about 0.120″ wide. In other words, thewidth of the slit 38 in the body portion 48 is almost twice that of theregion 50 of minimum width. From the region 50 of minimum width the slit38 tapers outward to the slit opening 36, where it attains a preferredwidth of about 0.200″. This tapered configuration acts as lead-in forinsertion of the syringe Luer 28 into the slit 38. The slit 38 may alsohave beveled corners 52 at its lower end, opposite the neck 42. At itslower end the slit 38 connects to the lead lumen 46 to facilitate fluidcommunication between the slit 38 and the lead lumen 46. The lead lumen46 preferably has a lead-in chamfer 54 and a beveled transition 56 tothe slit 38. The preferred inside diameter of the lead lumen 46 is about0.040″.

[0057] In the side views of FIGS. 7A and 7B, it may be seen that theseal 32 has a T-shaped cross section before installation in the housing30, with the flange 44 forming the cross portion of the “T”. Viewed fromthe side, the slit 38 is uniformly thin, i.e. of no or virtually nothickness, as it runs from the top of the seal 32 to the lead lumen 46.However, upon installation in the housing 30, the thickness of the slit38 (when viewed from the side) will vary somewhat as will be explainedin greater detail below.

[0058] FIGS. 8A-8D show the effects, in terms of sealing performance, ofthe varying width of the slit 38 after introduction of a syringe Luer 28into the slit 38. (The syringe Luer 28 is not shown in FIG. 8A forpurposes of clarity.) FIG. 8B shows the arrangement of the slit 38 andthe syringe Luer 28 at the region 50 of minimum width, when the Luer 28has been fully inserted into the slit 38. Due to the relative narrownessof the slit 38 at the region 50, the slit 38 draws up againstsubstantially the entire perimeter of the syringe Luer 28 at thatlocation, creating a relatively tight perimeter seal between the slit 38and the Luer 28. In other words, the perimeter of the open slit 38 atthe region 50 is less than the circumference of the Luer 28.

[0059]FIGS. 8C and 8D show that where the slit 38 is wider (i.e., in thebody portion 48 of the slit and the transition from the region 50) theslit no longer contacts the entire perimeter of the syringe Luer 28,leaving gaps 57 on one or both sides and the end of the Luer 28. Inother words, the perimeter of the open slit in the body portion 48 isgreater than the circumference of the Luer 28. As will be discussed ingreater detail below, this arrangement of a slit-Luer seal near the topof the slit 38 and a fluid-occupiable volume (in the form of the gaps57) below the slit-Luer seal, promotes a positive-flow function for thevalve 20 when the syringe Luer 28 is withdrawn.

[0060]FIGS. 3, 4, and 9 show a preferred configuration of the housing 30and the installation of the seal 32 therein. The housing 30 ispreferably formed of molded polycarbonate, or alternatively formed fromany suitable thermoplastic. The housing 30 has a seal holder 58 attachedto the Luer lock 34; the seal holder preferably has a cylindricalconfiguration, but may comprise any shape or construction sufficient tohold the seal 32 on or in the housing 30 without interfering withoperation of the valve 20. The seal holder has an axial opening 60opposite the Luer lock 34, and first and second side openings 62 a, 62 bwhich have first and second top edges 63 a, 63 b that comprise the edgesof the side openings nearest the axial opening 60. A lead cannula 64(best seen in FIG. 9) extends from the Luer lock 34 toward the axialopening 60 and contains an internal lumen 66 which is in fluidcommunication with a lumen 68 in the Luer lock 34. The lead cannula 64is preferably substantially cylindrical or frusto-conical in shape andcentered about an axis that is substantially parallel to or collinearwith the longitudinal axis of the housing 30. A pair of lugs 70 arepositioned on the end of the seal holder 58 near the axial opening 60,to permit a Luer lock or other threaded connection (not shown) tothreadably engage the housing 30 at the axial opening 60.

[0061] As best seen in FIGS. 3 and 4, most of the seal 32 is situatedwithin the seal holder 58, with the first and second lateral extensions43 a, 43 b of the seal 32 protruding from the first and second sideopenings 62 a, 62 b. The lead lumen 46 of the seal 32 is situated sothat the lead cannula 64 extends at least partway into the lead lumen,facilitating fluid communication between the seal 32 and the Luer lock34. The flange 44 covers the axial opening 60 and contacts the adjacentedges of the opening. Preferably, the distance between the axial opening60 and the top edges 63 a, 63 b of the side openings 62 a, 62 b isslightly larger than the distance between the flange 44 and theshoulders 43 c, 43 d of the lateral extensions 43 a, 43 b. Thisarrangement results in the application of a tensile force or preload tothe seal 32 between the flange 44 and the lateral extensions 43 a, 43 b.The preload arises as the shoulders 43 c, 43 d bear against the topedges 63 a, 63 b and the flange 44 bears against the edges of the axialopening 60. The preload causes the flange 44 to assume a slightlybowl-shaped or concave configuration as the edges of the axial opening60 bear against the underside of the flange 44. The bowl-shaped flange44 thus serves as a lead-in for the insertion of the syringe Luer 28into the slit opening 36 (best seen in FIG. 2), and tends to pinchclosed the slit opening 36 and thus enhances the ability of the seal 32to prevent fluid flow. The preload also prevents buckling of the sealalong its longitudinal axis and maintains the sides of the slit 38 inclose proximity along their entire length. The preload thus promotes arelatively thin slit below the flange 44, which enhances the sealingperformance of the slit 38.

[0062] FIGS. 10-14 illustrate the function of the valve 20 as a syringeLuer 28 is inserted into and withdrawn from the slit 38. FIG. 10 showsthe valve 20 prior to insertion of the syringe Luer 28; at this pointthe slit 38 defines a substantially closed or highly restricted flowpath through the seal 32, marked by a very thin (or substantiallynonexistent) path thickness T_(min) between slit walls 72 a, 72 b. Thisthin or nonexistent path thickness T_(min) prevails along most orsubstantially all of the length of the slit 38 below the flange 44. Thiscondition restricts fluid flow through the seal 32 so as to seal off thecatheter 22 (see FIG. 1) or other medical device connected to the Luerlock 34. At this point the slit 38 also defines a relatively smallinterior volume V_(min) within the seal 32, between the slit walls 72 a,72 b. (As used herein in reference to an interior volume of the seal,“relatively small” means a volume that is either nonexistent orclinically negligible in size.) In this initial state, the seal 32 issituated upon the lead cannula 64 such that substantially none of thelead cannula 64 extends into the slit 38.

[0063]FIGS. 11 and 12 show the valve 20 after the syringe Luer 28 hasbeen completely inserted into the slit 38. The seal 32 has also beenstretched or forced downward onto the lead cannula 64, at least part ofwhich penetrates into the slit 38 itself. At this point the slit 38defines an expanded flow path through the seal 32, in that the slitwalls 72 a, 72 b have spread to a path width T_(max). The seal 32 thuspermits fluid to flow between the syringe 24 and the catheter 22. Inaddition, the slit 38 now defines a larger or maximum interior volumeV_(max). V_(max) comprises the entire space between the slit walls 72 a,72 b less the volume taken up by the cannula (but not the internallumen) of the syringe Luer 28 and less that portion of the lead cannula64 which has penetrated into the slit 38. Accordingly, under pressureexerted via the syringe 24 an amount of fluid substantially equivalentto V_(max) now fills the slit 38 between the slit walls 72 a, 72 b. Thisis also shown as gaps 57 in FIGS. 8C and 8D.

[0064]FIGS. 13 and 14 show the function of the slit 38 as the syringeLuer 28 is withdrawn from the valve 20. As the syringe Luer 28 and leadcannula 64 exit the slit, the slit walls 72 a, 72 b retract tosubstantially their original configuration to once again define a narrowpath width (approaching T_(min)) between them. This retraction of theslit walls 72 a, 72 b reduces the volume between the walls; that is, theinternal volume within the slit 38 is decreasing from V_(max). Thus theamount of fluid within the slit must also decrease from V_(max).Accordingly, the retracting slit walls 72 a, 72 b displace the fluidfrom the slit 38 as the syringe Luer 28 is withdrawn.

[0065] The fluid thus displaced cannot flow out of the slit 38 throughthe top of the seal 32. As detailed above with regard to FIGS. 8A-8B,the slit 38 maintains a tight seal against the syringe Luer 28 at theregion 50 of minimum width as the syringe Luer 28 is withdrawn. Inaddition, the displaced fluid cannot flow into the interior of thesyringe 24 at all times relevant to the use of the valve 20. Therefore,substantially all of the displaced fluid must exit the slit 38 throughthe lead cannula 64 and Luer lock 34, resulting in positive flow fromthe valve 20 upon withdrawal of the syringe Luer 28.

[0066] FIGS. 15-18 show variations on the valve 20 disclosed above,which variations may be desirable under certain operating conditions.For example, as seen in FIGS. 15 and 16 the housing 30 may have a break74 running vertically between the axial opening 60 and one or both ofthe side openings 62 a, 62 b. The break 74 permits the seal holder 58 tospread open as a Luer slip 28 (as opposed to a Luer lock 76 shown inFIG. 17) is inserted into the seal 32. This spreading action has beenfound to be advantageous for using the valve 20 with a Luer slip 28, asthe valve 20 becomes less likely to squeeze or pinch the Luer 28 out ofthe seal 32.

[0067]FIG. 18 shows an alternative configuration of the housing 30, witha curved or streamlined appearance in comparison to the housingdisclosed above. Both this type of housing or the type disclosed above,may have an external coating or layer of a relatively soft, pliantmaterial such as a thermoplastic elastomer to enhance operator comfortand to promote the theme of a valve 20 that provides a connectionwithout the use of sharp, puncturing elements such as needles or blades.

[0068] FIGS. 19A-21 depict a preferred method of making the seal 32.First, a pair of preforms 202 a, 202 b are molded between first andsecond mold pairs 204 a, 204 b and 206 a, 206 b respectively. Eachpreform 202 has a generally planar portion 208 that, in the completedseal 32, forms a wall of the slit 38 (see FIGS. 6A-7B). A flange portion210 is also integrally molded into both preforms 202. The sides of theflange portion 210 are preferably set back from the upper face of theplanar portion 208, to provide a space for overmold material (discussedin further detail below) to flow between and connect the flange portions210. The molding of the preforms 202 is accomplished using conventionaltechniques and equipment, preferably by injecting a thermoset materialinto the cavity formed between the mold pairs 204 a, 204 b and 206 a,206 b and heating the molds and/or material to the set temperature ofthe specific material used. Pressure may be applied as needed to preventmaterial from leaking between the halves of the mold.

[0069] After this initial molding step, the mold halves 204 a, 206 a,with the preforms 202 a, 202 b still positioned in them, are pressedtogether with an overmold plate 212 positioned between the mold halves,as depicted in FIGS. 19B-19C. The overmold plate 212, best seen in FIG.20 (with the outline of the preforms 202 also shown in phantom),comprises a generally planar plate body 214 with an overmold opening 216cut into the body 214. The overmold opening 216 has a plan perimeterthat conforms to the outer edges of the completed seal 32, and mayinclude a mandrel 218 that projects from the lower portion of theopening 216 and forms the lead lumen 46 (see FIGS. 6A-7B) during theovermold process, as will be discussed in greater detail below. Thecontacting faces of the mold halves 204 a, 206 a and the overmold plate212 are advantageously substantially planar. Thus the mold halves 204 a,206 a, plate 212, and preforms 202 a, 202 b define a mold cavity orvolume 220 between the walls of the overmold opening 216 and the outeredges of the preforms 202 a, 202 b, and between the faces of the moldhalves 204 a, 206 a.

[0070] With the mold apparatus (mold halves 204 a, 206 a and overmoldplate 212) arranged as shown in FIG. 19C, additional thermoset materialis injected into the mold apparatus to fill the mold cavity 220 and formthe remainder of the seal 32. Preferably, the additional material isinjected soon (i.e., a few seconds) after the preforms 202 are moldedand while they are still somewhat hot from the initial molding. Theadditional material injected into the mold cavity 220 bonds to the edgesof the preforms 202 and forms the edges of the slit 38 in the completedseal 32. In other words, the remainder of the seal is overmolded ontothe “sandwich” of preforms 202. Preferably, the preforms 202 are pressedtogether with sufficient force during the overmolding process to preventthe additional material from migrating between the contacting surfacesof the preforms 202. This preserves the patency of the slit 38 bypreventing the contacting faces of the preforms 202 from bonding to eachother during the overmold step.

[0071] The overmold plate 212 may be made with a thickness approximatelythe same as that of the “sandwich” of preforms 202 a, 202 b to define amold cavity 220 that, as described above, comprises the open spacebetween the walls of the overmold opening 216 and the outer edges of thepreforms 202 a, 202 b, and between the faces of the mold halves 204 a,206 a. This overmold opening thus also has a thickness approximatelyequal to that of the preform sandwich, and all or nearly all of theovermold material injected therein bonds only to the edges of thepreforms 202 a, 202 b. In an alternative embodiment, the overmold plate212 may have a thickness greater than the preform sandwich. Thisthicker, alternative overmold plate thereby defines a mold cavity thatalso includes open space that is created between the mold halves 204 a,206 a and the outer (i.e., facing away from the slit in the completedseal) faces of the preforms 202 a, 202 b. The mold halves 204 a, 206 aare preferably configured with projections, ridges, channels, gaps orthe like to create such space during this alternative overmold stepwhile pressing the preforms together as may be needed during theovermold. Accordingly, in this embodiment the overmold material bonds toboth the edges and to the outer faces of the preforms 202 a, 202 b. Inother words this alternative overmold step involves injecting theovermold material into a mold cavity that surrounds most or all of thepreform sandwich, rather than overmolding to the only the edges of thepreforms.

[0072] It is preferred that the material added in the overmold step issimilar to that utilized in molding the preforms 202; however, in otherembodiments the preform material and the overmold material may comprisedifferent but nonetheless suitable materials for manufacturing the seal,as discussed above. Therefore as used herein “a flexible material”refers to any material selected from the class of suitable sealmaterials as disclosed.

[0073] After the overmolding is complete, the mold halves 204 a, 206 aare removed from the seal plate 212, which now contains a substantiallycompleted seal 32, as seen in FIGS. 19D-19E. The completed seal 32 iseasily removed from the seal plate 212, and the seal thus formedcomprises, as discussed above, a unitary mass of molded material withthe slit arranged within it.

[0074] Although this invention has been disclosed in the context ofcertain preferred embodiments and examples, it will be understood bythose skilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. Thus, it is intended that the scope of the present inventionherein disclosed should not be limited by the particular disclosedembodiments described above, but should be determined only by a fairreading of the claims that follow.

What is claimed is:
 1. A medical valve for selectively permitting fluidto flow between a first medical device and a second medical device, thevalve comprising: a housing having an interface suitable for receiving aconnector portion of the first medical device; and a seal made of aflexible material, the seal having a downstream end in fluidcommunication with the interface, an upstream end suitable for receivingat least a portion of the second medical device, and a normallysubstantially closed passage in fluid communication with the downstreamend and the upstream end, the passage being relatively wide in theregion of the upstream end and the passage being relatively narrow inthe region of the downstream end, the passage adapted to have arelatively small interior volume when in an undisturbed state and alarger interior volume upon the introduction of the second medicaldevice into the upstream end of the passage, the passage adapted toretract to define a restricted flow path and a relatively small interiorvolume upon the withdrawal of the second medical device from the seal,the upstream end adapted to initially be substantially sealed againstthe inserted portion of the second medical device as the second medicaldevice is withdrawn, so that a fluid occupying the interior volume isforced toward the downstream end as the passage walls collapse.
 2. Themedical valve defined in claim 1, wherein the seal comprises: a leadlumen formed in the downstream end of the body and in fluidcommunication with the passage; a neck formed in the upstream region ofthe seal; and a transverse flange in the upstream region of the seal,the transverse flange having at least one opening in fluid communicationwith the passage.
 3. The medical valve of claim 2, wherein the leadlumen is centered on an axis substantially parallel to or collinear witha longitudinal axis of the seal.
 4. The medical valve of claim 2,wherein the seal comprises a substantially rectangular slab of flexiblematerial and the neck is coplanar with the body.
 5. The medical valve ofclaim 1, wherein the passage in the undisturbed state tapers inwardlyfrom the upstream end to a region of minimum width.
 6. The medical valveof claim 5, wherein the passage in the undisturbed state tapersoutwardly from the region of minimum width toward the downstream end. 7.The medical valve of claim 2, wherein the seal has first and secondlateral portions and the housing further comprises: a seal holderattached to the interface, the seal holder comprising a hollowcylindrical member that extends from the interface and has an axialopening opposite the interface, and first and second side openings; alead cannula attached to and in fluid communication with the interfaceand extending from the interface toward the axial opening, wherein theseal is disposed within the seal holder such that the lead cannulaextends at least partially into the lead lumen, the flange extendsacross the axial opening, and the first and second lateral portions ofthe seal body extend into the first and second side openings.
 8. Themedical valve of claim 7, wherein the lead cannula is centered on anaxis substantially parallel to or collinear with a longitudinal axis ofthe housing.
 9. The medical valve of claim 1, wherein a lead cannulaattached to and in fluid communication with the interface extends fromthe interface into the downstream end of the seal, an end of the leadcannula being disposed within the passage at a location in the upstreamdirection from the furthest downstream periphery of the interior volumeof the seal.
 10. The medical valve of claim 7, wherein the seal isadapted to move within the housing in the downstream direction uponinsertion of the second medical device and to move within the housing inthe upstream direction upon withdrawal of the second medical device. 11.The medical valve of claim 10, wherein the lead lumen of the sealexpands as the seal moves in the downstream direction and the leadcannula extends further into the interior of the passage of the seal.